A random sample of 500 registered voters in Phoenix is asked if they favor the use of oxygenated fuels year-round to reduce air pollution. If more than 400 voters respond positively, we will conclude that at least 60% of the voters favor the use of these fuels.
(a) Find the probability of type I error if exactly 60% of the voters favor the use of these fuels.
(b) What is the type II error probability B if 75% of the voters favor this action? Hint: use the normal approximation to the binomial.